Brush alignment platform

ABSTRACT

A brush alignment apparatus and method of using the same for aligning a hollow cylindrical brush on a cylindrical roller member comprising first and second ends and an outer surface defining a internal cavity, provided with a plurality of orifices extending from the outer surface to the internal cavity, a first receptacle having a channel running therethrough in fluid communication with the first end of the roller member, a second receptacle, a spine member, a first support arm supporting the first end of the roller member and a second arm supporting the second end of the roller member. In operation, the brush is applied onto the surface of the roller such that the inner surface of the brush and the outer surface of the roller are in frictional communication with one another, a layer of fluid is generated between the surfaces of the roller and the brush sufficient to substantially dissipate any frictional contact between the brush and the roller, the layer is maintained between the surfaces of the roller and the brush for sufficient time and at sufficient strength to allow the brush to attain a position of static alignment, at which time the layer is allowed to dissipate thereby returning the brush to a position of frictional communication with the surface of the roller, while substantially retaining it in a state of static alignment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a brush alignment platform and, moreparticularly, to an alignment jig that provides for the disposition of abrush on a roller, in static alignment, by creating a layer of fluidbeneath the brush to successively unseat the brush from the roller andbring the brush substantially into static alignment.

2. Description of the Invention Background

As is known in the art, in the course of the process of manufacturing asemiconductor device, impurities will become deposited on the surface ofthe semiconductor wafer or substrate. If these contaminants are allowedto remain in the wafer throughout the manufacturing process, the qualityand the yield of the production process will be negatively affected.Therefore, various cleaning processes are typically employed throughoutthe manufacturing process in an attempt to eliminate these impuritiesfrom the surface of the semiconductor.

One such known cleaning apparatus includes rotating a substantiallycylindrical brush, having a plurality of cleaning tips thereon, alongthe surface of the semiconductor to remove impurities. In practice, thebrush has a length equal to or greater than the diameter of the wafer tobe cleaned. The cylindrical brush is manually seated onto a rollershaft. The shaft is then mechanically rotated about its axis while beingmoved along a diameter of the wafer. In the alternative, the waferitself is also rotated about its center point while the brush is rotatedabout its axis. In either case, the cleaning tips are brought intocontact with the surface of the wafer while a cleaning solution isintroduced onto the surface of the wafer. As such, the entire surface ofthe wafer is contacted and cleaned by the rotating action of thecleaning tips. As described, the cleaning apparatus can be employed toclean either the top or bottom side of the semiconductor wafer. Suchwafer cleaning apparatus are known in the art by and sold under thetrademark of OnTrak™ by OnTrak Systems, Inc. of Milpitas, Calif.

In such a cleaning apparatus, for the brush to successfully clean thesurface of the wafer, it is critical that the brush be evenly disposedalong the length of the roller shaft so that the cleaning tips areevenly aligned throughout the surface of the brush. However, due to theneed for the brush to be in close communication with the surface of theroller, the inner diameter of the brush is designed to be equal to orless than the outer diameter of the roller. Therefore, it is necessaryto manually deform and stretch the brush to fully seat it onto theroller. Manual application of the brush is very difficult to accomplishwithout twisting and unevenly disposing the brush along the shaft. Sucha misalignment of the brush creates an uneven placement of the cleaningtips about the surface area of the brush which ultimately leads to anuneven cleaning of the surface of the wafer by the brush. The mostcommon method of aligning the brush is to manually re-seat it onto theshaft. This method involves applying and aligning the brush by hand.Typically, it is time consuming and only partially effective.

Increasing the inner diameter of the brush will decrease the tendencyfor the brush to be unevenly disposed along the shaft. However,increasing the diameter of the brush will also decrease the frictionalcontact between the brush and the shaft. This typically leads toslippage between the brush and the roller which causes premature wearingof the brush and uneven cleaning of the wafer. Thus, increasing thediameter of the brush to eliminate this problem is undesirable. Othermethods designed to reduce the misalignment of the brush on the shaft,such as lubricating the points of contact between the brush and theshaft, also lead to such slipping and are thus equally undesirable.

Thus, the only suitable method known in the art of aligning the brush onthe roller is to do so by hand. This manual alignment process istypically slow, cumbersome and only partially effective. None of theknown cleaning apparatus in the prior art provide an adequate solutionto the problem of proper brush alignment.

The subject invention is thus directed toward a brush alignmentapparatus and method which addresses, among others, the above-discussedneeds and provides an apparatus and method for aligning a cleaning brushon a roller such that it is evenly disposed about the entire surfacearea of the shaft with minimal effort and time expended by the operator.

SUMMARY OF THE INVENTION

The present invention provides a brush alignment apparatus and methodfor installing brushes onto a roller in a uniformly disposed manner.This invention also provides a brush alignment apparatus and method thatallows for the installation of brushes onto rollers with decreasedeffort and time expended on the part of the operator. Further, theinstant invention serves to provide a brush alignment apparatus andmethod that provides for improved operation and performance of thebrush.

In accordance with a preferred form of the present invention, there isprovided a brush alignment apparatus and jig. The brush alignmentapparatus and jig disclosed herein includes a roller having a internalcavity running therethrough and a plurality of orifices disposed aboutthe outer surface of the roller that allow for fluid communicationbetween the internal cavity and outer the surface of the roller. Asource of pressurized fluid is provided in communication with theinternal cavity, such that when a brush is disposed upon the roller andfluid is fed into the internal cavity, the fluid will flow through theplurality of orifices and create a layer of fluid between the outersurface of the roller and the inner surface of the brush. The rate atwhich the liquid or gas is fed through the cylinder is sufficient todistend the brush so that it is no longer substantially in frictionalcommunication with the outer surface of the roller and is substantiallyseparated from the roller by the layer of fluid. While supported by thislayer, the brush will return to its natural aligned state. When the flowof fluid is terminated, the layer of fluid between the outer surface ofthe roller and the inner surface of the brush becomes insufficient tosupport the distended brush and the brush contracts to again contact theouter surface of the roller. Though the brush is again in contact withthe roller, the brush remains in its natural aligned state.

Accordingly, the present invention provides solutions to the problemsassociated with existing rollers and roller jigs. The reader willappreciate that these and other details, objects and advantages willbecome apparent as the following detailed description of the presentpreferred embodiments thereof proceeds or may be learned from practiceof the invention. The objects and advantages of the invention may berealized and obtained by means of the instrumentalities and combinationsparticularly set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, preferred embodiments of the presentinvention are shown, wherein like reference numerals are employed todesignate like parts and wherein:

FIG. 1 is a cut-away side perspective view of an embodiment of thepresent invention in use on a platform apparatus;

FIG. 2 is a cut-away side perspective view of the embodiment in FIG. 1;

FIG. 3 is a side perspective view of the embodiment in FIG. 1 without abrush placed thereon;

FIG. 4 is a side perspective view of the embodiment in FIG. 1 with abrush placed thereon, prior to alignment with the present invention;

FIG. 5 is a side perspective view of the embodiment in FIG. 1 with abrush placed thereon from FIG. 4 after alignment with the presentinvention;

FIG. 6 is a cross-sectional view of the embodiment in FIG. 1 used in thepreferred embodiment of the present invention;

FIG. 7 is a cross-sectional view of the embodiment in FIG. 1 used in thepreferred embodiment of the present invention;

FIG. 8 is a side view of an On-Trak™ scrubber apparatus on which theembodiment in FIG. 1 may be utilized showing an image in phantom of theembodiment in FIG. 1 in use thereon;

FIG. 9 is a side view of another On-Trak™ scrubber apparatus on whichthe embodiment in FIG. 1 may be utilized showing an image in phantom ofthe embodiment in FIG. 1 in use thereon; and

FIGS. 10a-c are side cross-sectional views of the embodiment in FIG. 1being loaded and unloaded from the platform apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings for the purposes of illustrating preferredembodiments of the invention only, and not for purposes of limiting thesame, the Figures generally show a brush alignment platform. Moreparticularly and with reference to FIG. 1, a brush alignment platform isshown generally at 30 for aligning a brush 10 on a roller 8. Theplatform 30 generally supports a roller 8, with a internal cavity 20running therethrough and a plurality of orifices 26 in the surfacethereof that allow for fluid communication between the internal cavity20 and the outside surface 9 of the roller 8.

The roller 8 is cylindrical in shape and has a generally circular crosssection. The body of the roller 8 is substantially hollow and includesan internal cavity 20 running therethrough. A plurality of orifices 26are disposed about the outer surface 9 of the roller 8. The orifices 26pass through the surface of the roller 8 and enter the internal cavity20. As such, they are in fluid communication with the internal cavity 20and provide for the free flow of liquid or gas between the internalcavity 20 and the surface 9 of the roller 8. At the distal ends of theroller are disposed caps 22 and 24, respectively. At one end, the cap 22is provided with a channel 21 running therethrough substantially alongthe center axis of the cap 22. In the preferred embodiment, the channel21 is of equal cross sectional area to the internal cavity 20 in theroller at one end of the cap 22 and tapers to a smaller cross sectionalarea at the other end of the cap 22. The channel 21 allows for fluidcommunication between the internal cavity 20 and the area outside of theroller 8. At the other end of the roller 8, the cap 24 is adapted to beremoveably attached to a roller drive axle 40. As will be appreciated byone of ordinary skill in the art, such axles possess various shapes andthus cap 24 can also take various shapes as required to be attached tothe drive axle 40.

The brush 10 is of a generally cylindrical shape. To allow forsufficient frictional contact between the brush 10 and the roller 8, thecross sectional dimensions of the inner surface 11 of the brush 10 aregenerally equal to or slightly smaller than those of the outer surface 9of the roller 8 (see FIGS. 5 and 6). The brush 10 is preferably formedfrom a rubberized material, such as polyvinyl alcohol (PVA), polyvinyldiflouride (PVDF), Teflon or the like. As such, the brush is flexibleand has the property of being expandable, stretchable and deformable tobeyond its normal size when pressure is applied thereto. In particular,the brush preferably has a 30% compressive stress of between 20-90(g/cm³), a tensile strength of between 100-300%, and a water absorptionspeed of between 700-1500% of weight.

In operation, when the brush 10 is displaced along the length of theroller 8, it is able to be stretched to fit over an outer surface 9 ofthe roller 8 that is at least as large or larger than the inner diameterof the brush 10. The friction alone generated by the contact between theouter surface 9 of the roller 8 and the inner surface 11 of the brush10, is sufficient to hold the brush 10 in place without the need foradditional adhesives or attachment devices.

The outside surface of the brush is provided with a plurality ofbristles or tips 12. As seen in FIG. 5, when the brush is in a state ofequilibrium, as defined by a state of rest in which the brush in uniformtension and has uniform consistency throughout, the tips 12 arepreferably arrayed in a generally uniform pattern and the material ofthe brush 10 is displaced with equal thickness, consistency and tensionthroughout its entire outer surface 14b and at the end surface 16b. Inoperation, uniform scrubbing cannot occur unless the brush is maintainedin this same uniform alignment even when fitted onto the roller 8.Though it is desirable to maintain this uniform alignment of the tips 12even after the brush 10 is disposed upon the roller 8, the process ofmanually maneuvering the brush 10 in close frictional contact with theroller 8 creates great difficulties in achieving such a uniform array ofthe tips 12. As can be seen in FIG. 4 when the brush 10 is manuallyplaced onto the roller 8, the brush 10 is displaced with unequalthickness and inconsistent tension throughout its entire outer surface14a and end surface 16a.

The alignment apparatus 30 includes upper and lower support arms 32 and34, respectively, joined by a support spine 31. The arm 32 is furtherprovided with an inlet 36 in fluid and gaseous communication with thechannel 21 and the internal cavity 20 and is provided with threads,clamps or some other means of accepting the nozzle of a fluid source.The brush arm 32 is biasable along the spine 31 between an open positionin which the end 24 of roller 8 may be inserted into the bottomreceptacle 35 in the lower arm 34, and a closed position in which theboth ends 22 and 24 of roller 8 are inserted into receptacles 33 and 35,respectively, and the apparatus is ready for operation (FIGS. 10a-c). Anadjustment button 38 is provided on the top brush arm 32 to regulatemovement of the top arm 32 along the spine 31. Actuation of theadjustment button 38 provides for free movement of the top arm 32 alongthe length of the spine 31. Releasing the adjustment button 38 restrictsmovement of the top arm 32 to a single position. Thus, the arm 32 may bemoved between an open and a closed position as is necessary to insertand remove the roller 8. It will be appreciated that other means offreeing the roller 8 from the arms 32 and 34, such as detaching arm 8from the apparatus entirely, are apparent to those of ordinary skill inthe art.

The present invention provides a novel apparatus and method for aligningthe brush 9 on the roller 8, with the tips 12 in a uniform pattern, oncethe brush 10 has been manually applied to the roller 8. In practice, abrush 10 is manually applied to the outer surface 9 of a roller 8. Ascan be seen in FIG. 4 at this point, the edges and surfaces 16a and 14aof the brush 10 are generally not aligned uniformly or consistentlyalong the surface 9 of the roller 8. The adjustment button 38 isactuated, the arm 32 is biased into the open position and end 24 of theroller 8 is placed into the receptacle 35. The adjustment button 38again actuated and arm 32 is returned to the closed position, with end22 of the roller 8 placed in receptacle 33. A fluid source, such as ahose attached to a fluid reservoir (not pictured), is attached to theinlet 36 and the fluid is pumped under pressure into the inlet 36. Oneof ordinary skill in the art will appreciate that such fluid maycomprise for example air, nitrogen gas, or water. However, that anyliquid or gas possessing similar characteristics when acted upon bypressure will suffice. The fluid flows from inlet 36 through channel 21and into internal cavity 20. When sufficient pressure exists in internalcavity 20, the fluid escapes from internal cavity 20 through theplurality of orifices 26. The fluid leaving the internal cavity 20 fromthe orifices 26 is of sufficient strength and pressure to form a layerof fluid between the outer surface 9 of the roller 8 and the innersurface 11 of the brush 10 that deforms the brush 10 outward, away fromthe outer surface 9 of the roller 8 on which it was seated. Whiledistended by the cushion of fluid between the inner surface 9 of thebrush 11 and the outer surface 9 of the roller 8, the roller is nolonger substantially in frictional contact with the roller 8 and is heldin place on the roller 8 by brush stops 46 and 47. As such, the brush 8is allowed to return to its resting equilibrium shape in which theplurality of tips 12 are arrayed in alignment with each other throughoutthe entire surface area of the brush 10. It will be appreciated that thepressure required to provide the necessary distention of the brush willvary depending upon the material characteristics and size of the brush.As can be seen in FIG. 5, the edges and surfaces 16b and 14b of thebrush 10 are generally now aligned uniformly along the surface 9 of theroller 8. The flow of fluid is then terminated, the cushion of fluidbetween the roller 8 and the brush 10 collapses and the brush 10 returnsto its frictional contact with the surface 9 of the roller 8.

FIGS. 8 and 9 depict the On-Trak™ scrubber unit 50 with which thepreferred embodiment of the present invention is to be used. In FIG. 8the scrubber unit 50 is adapted to be used with a single brush 10 forcleaning a single side of the semiconductor wafer 70 at one time. Inoperation, a semiconductor wafer 70 is held in contact with the tips ofthe brush 10 (shown in phantom) by wafer carrier 62. The wafer 70 isheld in place while the brush 10 is rotated about drive shaft 56 andmoved from one edge of the wafer 70 to the other along the diameter ofthe wafer 70. This process is then repeated as necessary until theentire surface of the wafer 70 has been cleaned. During this process,cleaning fluid may be discharged from a cleaning fluid source, asrepresented by reference number 53, through cleaning solvent discharge54 and onto the surface of the wafer 70 to aid in the cleaning of thewafer 70. In alternative embodiments, the brush 10 may be held in afixed position relative to the wafer 70 and be rotated about drive shaft56 while the wafer 70 is spun about its center to accomplish the sameresult. The scrubber 50 in FIG. 9 operates in the same manner as theunit in FIG. 8, but is additionally adapted to be used with a secondbrush 10 so as to clean both surfaces of the wafer 70 simultaneously.

Those of ordinary skill in the art will, of course, appreciate thatvarious changes in the details, materials and arrangements of partswhich have been herein described and illustrated in order to explain thenature of the invention may be made by those skilled in the art withinthe principle and scope of the invention as expressed in the appendedclaims.

What is claimed is:
 1. A cleaning apparatus for cleaning the surface ofa wafer comprising:a wafer tray for holding the wafer; a cylindricalroller member mounted for rotation about its longitudinal axis; a hollowcylindrical brush member having a plurality of cleaning tips disposedthereon positioned to contact the surface of a wafer held in the wafertray; a source of cleaning fluid; a spray tip for discharging cleaningfluid from the source onto the surface of the wafer; and a brushalignment device for aligning the brush member on the roller member, theroller member having first and second ends and an outer surface definingan internal cavity provided with a plurality of orifices extendingthrough the outer surface to the internal cavity, the brush alignmentdevice comprising:a first receptacle having a channel therethrough influid communication with the first end of the roller member; a firstsupport arm supporting the first receptacle; a second receptacle for thesecond end of the roller member; a second support arm supporting thesecond receptacle; and a spine member connected to and supporting thefirst support arm and the second support arm.
 2. The cleaning apparatusof claim 1, wherein the wafer tray is rotatable about its center.
 3. Thecleaning apparatus of claim 1, wherein the roller is rotatable about itslongitudinal axis while the wafer tray is rotatable about its center. 4.The cleaning apparatus of claim 1, wherein the roller is moveablelaterally across the length of the wafer tray.
 5. The cleaning apparatusof claim 1, further comprising a source of pressurized fluid in fluidcommunication with the channel in the first receptacle.
 6. The cleaningapparatus of claim 1, wherein the first arm further comprises a firstbrush stop adjacent the first end of the roller.
 7. The cleaningapparatus of claim 1, wherein the second arm further comprises a secondbrush stop adjacent to the second end of the roller.
 8. The cleaningapparatus of claim 1, wherein the first arm is adjustably connected tothe spine member.
 9. The cleaning apparatus of claim 1, wherein thebrush member is formed of a resilient material.
 10. The cleaningapparatus of claim 1, wherein the brush member is maintained on theroller member by frictional engagement therebetween.
 11. The cleaningapparatus of claim 1, wherein an inner surface of the brush member has across-sectional diameter generally equal to or smaller than across-sectional diameter of the outer surface of the roller member. 12.A cleaning apparatus for cleaning the surface of a wafer comprising:awafer tray; a cylindrical roller member rotatable about its longitudinalaxis, the roller member having first and second ends and an outersurface defining an internal cavity provided with a plurality oforifices extending through the outer surface to the internal cavity; ahollow cylindrical brush member mounted and aligned on the rollermember, said brush member having a plurality of cleaning tips disposedthereon positioned to contact the surface of the wafer held in the wafertray; a source of cleaning fluid; a spray tip in communication with thesource of cleaning fluid and directed toward the surface of the wafer;and a brush alignment device comprising:a first receptacle having achannel therethrough in fluid communication with the first end of theroller member; a first support arm supporting the first receptacle; asecond receptacle for the second end of the roller member; a secondsupport arm supporting the second receptacle; and a spine memberconnected to and supporting the first support arm and the second supportarm.
 13. The cleaning apparatus of claim 12, wherein the wafer tray isrotatable about its center.
 14. The cleaning apparatus of claim 12,wherein the roller is rotatable about its longitudinal axis while thewafer tray is rotatable about its center.
 15. The cleaning apparatus ofclaim 12, wherein the roller is moveable laterally across the length ofthe wafer tray.
 16. The cleaning apparatus of claim 12, wherein thefirst arm further comprises a first brush stop adjacent the first end ofthe roller.
 17. The cleaning apparatus of claim 12, wherein the secondarm further comprises a second brush stop adjacent to the second end ofthe roller.
 18. The cleaning apparatus of claim 12, wherein the firstarm is adjustably connected to the spine member.
 19. The cleaningapparatus of claim 12, wherein the brush member is formed of a resilientmaterial.
 20. The cleaning apparatus of claim 12, wherein the brushmember is maintained on the roller member by frictional engagementtherebetween.
 21. The cleaning apparatus of claim 12, wherein an innersurface of the brush member has a cross-sectional diameter generallyequal to or smaller than a cross-sectional diameter of the outer surfaceof the roller member.
 22. A cleaning apparatus for cleaning the surfaceof a wafer comprising:a wafer tray; a cylindrical roller memberrotatable about its longitudinal axis, the roller member having firstand second ends and an outer surface defining an internal cavityprovided with a plurality of orifices extending through the outersurface to the internal cavity; a hollow cylindrical brush membermounted and aligned on the roller member, said brush member having aplurality of cleaning tips disposed thereon positioned to contact thesurface of the wafer held in the wafer tray; a source of cleaning fluid;a spray tip in communication with the source of cleaning fluid anddirected toward the surface of the wafer; and a brush alignment devicecomprising:a first receptacle having a channel therethrough in fluidcommunication with the first end of the roller member; a first supportarm supporting the first receptacle; a second receptacle for the secondend of the roller member; a second support arm supporting the secondreceptacle; a spine member connected to and supporting the first supportarm and the second support arm; and a source of pressurized fluid influid communication with the channel in the first receptacle.